Use of cationic surfactants in cosmetic preparations

ABSTRACT

The invention relates to a new use of cationic surfactants derived from the condensation of fatty acids and esterified dibasic amino acids, according to the following formula:  
                 
 
     where: X −  is Br − , Cl − , or HSO 4   − . R1: is linear alkyl chain from a saturated fatty acid, or hydroxyacid from 8 to 14 atoms of carbon bonded to the α-amino acid group through amidic bond. R2: is a lineal or branched alkyl chain from 1 to 18 carbon atoms or aromatic, and R3: is:  
                 
 
     and n can be from 0 to 4. This class of compounds turned out to be highly suitable for use as preservatives in cosmetic or dermatological preparations. A particularly suitable compound is the ethyl ester of the lauramide of arginine hydrochloride (LAE).

[0001] This invention relates to a novel use of cationic surfactants andpreparations according to this novel use.

[0002] Due to their composition, many cosmetic products are susceptibleto act as a culture medium for microorganisms, and this can causepossible alterations to the cosmetic preparation and constitute apossible risk to human heath as well. Thus, a cosmetic compositionrequires good protection against microbiological contamination.

[0003] A well-known substance used for the protection againstmicroorganisms is a cationic surfactant derived from lauric acid andarginine, in particular, the ethyl ester of the lauramide of thearginine monohydrochloride, hereafter named LAE. The chemical structureis described in the following formula:

[0004] This compound is remarkable for its activity against differentmicroorganisms, such as bacteria, fungi and yeasts and its use is knownin food and feed preparations. The compound is well-known to be harmlessto animals and humans. The minimum inhibitory concentrations of LAE areshown in the following table 1. TABLE 1 Kind Microorganism M.I.C. (ppm)Gram + Bacteria Arthrobacter oxydans ATCC 8010 64 Bacillus cereus varmycoide ATCC 11778 32 Bacillus subtilis ATCC 6633 16 Clostridiumperfringens ATCC 77454 16 Listeria monocytogenes ATCC 7644 10Staphylococcus aureus ATCC 6538 32 Micrococcus luteus ATCC 9631 128Lactobacillus delbrueckii ssp lactis CECT 372 16 Leuconostocmesenteroides CETC 912 32 Gram − Bacteria Alcaligenes faecalis ATCC 875064 Bordetella bronchiseptica ATCC 4617 128 Citrobacter freundii ATCC22636 64 Enterobacter aerogenes CECT 689 32 Escherichia coli ATCC 873932 Escherichia coli 0157H7 20 Klebsiella pneumoniae var pneumoniae CECT178 32 Proteus mirabilis CECT 170 32 Pseudomonas aeruginosa ATCC 9027 64Salmonella typhimurium ATCC 16028 32 Serratia marcenses CECT 274 32Mycobacterium phlei ATCC 41423 2 Fungi Aspergillus niger ATCC 14604 32Aureobasidium pullulans ATCC 9348 16 Gliocadium virens ATCC 4645 32Chaetonium globosum ATCC 6205 16 Penicillium chrysogenum CECT 2802 128Penicillium funiculosum CECT 2914 16 Yeast Candida albicans ATCC 1023116 Rhodotorula rubra CECT 1158 16 Saccharomyces cerevisiae ATCC 9763 32

[0005] It has now been detected that the product LAE and relatedcompounds are particularly suitable to be used in cosmetic preparations.

[0006] The use of the invention relates to cationic surfactants derivedfrom the condensation of fatty acids and esterified dibasic amino acids,according to the following formula:

[0007] where:

[0008] X⁻ is Br⁻, Cl⁻, or HSO₄ ⁻

[0009] R₁: is a linear alkyl chain from a saturated fatty acid orhydroxyacid from 8 to 14 atoms of carbon bonded to the α-amino acidgroup through an amidic bond.

[0010] R₂: is a linear or branched alkyl chain from 1 to 18 carbon atomsor an aromatic group.

[0011] R₃: is:

[0012] and n can be from 0 to 4.

[0013] The most preferred compound of the above class of compounds isLAE.

[0014] LAE can be used in cosmetic formulations and preparations thatare applied in the epidermis, the capillary system, lips, nails,external genital organs, or in the teeth and mouth cavity mucous, inorder to clean, perfume, or modify its aspect and/or change corporalsmells and/or protect a good physical fitness. At the same time LAEinhibits the growth of microorganisms in the cosmetic formulations andpreparations in which they are susceptible to develop, and also from themicroorganisms that can be introduced by the practical use of thecustomer.

[0015] The compositions of the invention have a medium which iscompatible with the skin, the mucous membranes, and hair. Thesecompositions can have the classical components such as: fatty compoundssuch as mineral oil, animals oil, vegetal oil, synthesis and siliconoils, and also alcohols, fatty acids and waxes; organic solvents,surface active agents, solubilizers and ionic and non ionic emulsifiers,thickening agents and jellying hydrophilic agents such as carboxyvinylicpolymers (e.g. carbomer), acrylic copolymers (e.g. acrylates andalkylacrylates), polyacrylamides, polysaccharides, natural gums (e.g.xanthan gum); thickening agents and jellying lipophilic agents such asmodified clays (e.g. bentonite), fatty acid metallic salts, hydrophobicsilica and polyethylene; perfumes and essential oils; softening agents;excipients; antioxidants; sequestering agents; opacifiers; filters;colouring compounds which may be either hydrosoluble or liposoluble, andpigments; and hydrophilic or lipophilic active ingredients. Thesecompositions can also contain further preservatives besides the onesused according to the invention.

[0016] The proportions of the components mentioned in the previousparagraph are the ones normally used in the mentioned applications.These components have to be applied without changing the preservativesystem of the invention.

[0017] According to the invention the compositions can be in differentcosmetic forms suitable for a topic application, such as:

[0018] a) Monophasic systems:

[0019] Aqueous or hydroglycolic solution that contain one or moresurfactants to be used for the cleaning of the skin, hair and mucousmembranes;

[0020] Aqueous, hydroalcoholic, hydroglycolic or oily solution that cancontain other additives to be used in the general care and/or protectionfor skin and/or mucous membranes;

[0021] Aqueous, hydroalcoholic, hydroglycolic or oily gel that cancontain other additives to be used in general care and/or protection forskin and/or mucous membranes;

[0022] Solid anhydride products that can contain other additives to beused in the general care and/or protection for skin and/or mucousmembranes;

[0023] b) Biphasic systems:

[0024] Aqueous, hydroalcoholic, hydroglycolic or oily gel that cancontain other additives to be used in general care and/or protection forskin and/or mucous membranes;

[0025] Solid anhydride products that can contain other additives to beused in the general care and/or protection for skin and/or mucousmembranes;

[0026] Emulsions formed by dispersion of a oil phase in a water phase(O/W) or inverse phase (W/O), to be used in general care and/orprotection of the face skin, body, hands and/or mucous; cleaning and/orremoval of make-up from the skin, mucous membranes, hair and/or mouthcavity; protection and/or skin care against solar radiation effects;colouring support and pigment to be applied to the skin.

[0027] c) And combinations of the other systems that form multiphasicsystems, suspensions and microemulsions.

[0028] The compositions previously mentioned can be used in differentforms such as foam, spray, or aerosol compositions and can contain apropulsion agent under pressure.

[0029] Thus, the compositions of the invention can have the aspect of acream, a lotion, a milk, an emulsion, a gel or an oil for the skin, abeauty mask, a salt, a gel, a foam/spray or an oil for bath and shower,or for making up and making-up cleaner for the face and eyes and anyother aspect known in the art.

[0030] The compositions according to the invention have been preparedaccording to the techniques well known for a person skilled in the art.

Procedure to Evaluate the Preservative Efficacy for LAE

[0031] The method is based on the Antimicrobial Effectiveness TestingUSP 24^(th) Edition, 1999 (pp. 1809-1811), in order to demonstrate thatthe antimicrobial activity of the compound aim of the patent is enoughto avoid the microbial growth that could have in the storage and use ofthe preparation, preventing the adverse effects of the contamination(Real Farmacopea Española, 1^(st) Edición, 1997).

[0032] This assay consists of the contamination of the protectingformulations with an inoculum mixture of 10⁸ cfu/mL concentration, foreach of the microorganisms, and the determination of the number ofviable cells in the time. This inoculum mixture is composed of thefollowing microorganisms: Pseudomonas aeruginosa ATCC 9027Staphylococcus aureus ATCC 6538 Candida albicans ATCC 10231 Aspergillusniger ATCC 16404 Escherichia coli ATCC 8739

[0033] The cosmetic composition to be analysed is divided into sterilecontainers with 50 g of product for each flask. Each container isinoculated with 0.5 mL of inoculum (10⁸ cfu/mL). The targetconcentration is 10⁶ cfu/mL, approximately. All the containers are keptat a temperature between 20-25° C. and are protected from light.

[0034] The level of the microbial contamination is checked at 0 hours, 7days, 14 days and 28 days. The number of colonies is evaluated bydilution in buffer peptone with the appropriate neutraliser agent of thepreservative. The culture media used for counting the microorganismsare: Soya triptone (35-37° C., 48 hours) for the determination ofbacteria; Sabouraud agar with chloramphenicol for fungi and yeast (25°C., 3-5 days).

[0035] According to Antimicrobial Effectiveness Testing USP 24thEdition, 1999 (pp. 1809-1811), an antimicrobial preservative isconsidered to be effective in topically used products made with aqueousbases or vehicles, non-sterile nasal products and emulsions, includingthose applied to mucous membranes, if:

[0036] Not less than 2.0 logarithm reduction from the initial calculatedbacteria's count is reached at 14 days and no increase from the 14 days'count at 28 days is detected; and

[0037] No increase from the initial calculated count of yeast and mouldsis observed.

EXAMPLES

[0038] Different examples of cosmetic preparations and formulations areprovided where the product has been assayed. Theses examples are a partof the preparations and formulations assayed.

Example 1

[0039] The composition of the cosmetic formulation in oil-in-wateremulsion with non-ionic surfactant, is (in g): Polysorbate 60 3.00Sorbitan stearate 2.00 Cetyl alcohol 1.00 Paraffinum 3.00 Isopropylmirystate 3.00 Caprylic-caproic triglycerides 3.00 Dimethicone 0.50Propylene glycol 3.00 Cellulose gum 0.25 Carbomer 940 0.10Triethanolamine 0.10 Aqua 100 c.s.p.

[0040] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the table 2. TABLE 2 With Without LAE LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 2.1 · 10⁶ 1.1 · 10⁶Fungi 1.6 · 10⁴ 1.7 · 10⁴ Yeast 3.7 · 10⁵ 5.6 · 10⁵  7 days Aerobes 2.1· 10⁶ 3.1 · 10³ Fungi 7.0 · 10² <9.9 · 10¹  Yeast 8.2 · 10³ 9.5 · 10² 14days Aerobes 6.2 · 10⁶ 3.3 · 10² Fungi 5.9 · 10² <9.9 · 10¹  Yeast 4.8 ·10³ 4.0 · 10²

[0041] At 28 days no increase has been detected from the 14 days' count.

Example 2

[0042] The composition of an oil-in-water emulsion with an ionicemulsifier, used as cosmetic formulation, is (in g): Stearic acid 1.70Glyceryl stearate S.E. 2.50 Cetyl alcohol 1.50 Paraffinum 3.00 Isopropylmyristate 3.00 Caprylic-caproic triglycerides 3.00 Dimethicone 0.50Propylene glycol 3.00 Cellulose gum 0.50 Triethanolamine 1.03 Aqua 100c.s.p.

[0043] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the table 3. TABLE 3 With Without LAE LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 7.4 · 10⁶ 2.7 · 10⁶Fungi 2.0 · 10⁴ 1.4 · 10⁴ Yeast 3.6 · 10⁴ 3.6 · 10⁴  7 days Aerobes 5.2· 10⁶ 1.6 · 10⁴ Fungi 8.8 · 10² <9.9 · 10¹  Yeast 4.7 · 10⁴ 1.0 · 10² 14days Aerobes 1.7 · 10⁷ 6.5 · 10² Fungi 7.0 · 10² <9.9 · 10¹  Yeast 1.0 ·10⁴ 1.0 · 10²

[0044] At 28 days no increase has been detected from the 14 days' count.

Example 3

[0045] The general composition for a cosmetic formulation, in water inoil emulsion with non-ionic emulsifiers, is (in g) Cetyl Dimethiconecopolyol 3.00 Isohexadecane 6.00 Paraffinum 8.00 Isopropyl myristate6.00 Caprylic-caproic triglycerides 4.00 Glycerin 5.00 Sodium chloride0.50 Aqua 100 c.s.p.

[0046] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 4. TABLE 4 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 1.6 · 10⁶  6.2 · 10⁶Fungi 2.0 · 10⁴  1.0 · 10⁴ Yeast 3.8 · 10⁴  7.0 · 10⁴  7 days Aerobes1.1 · 10⁶  1.8 · 10³ Fungi 5.0 · 10² <9.9 · 10¹ Yeast 9.0 · 10² <9.9 ·10¹ 14 days Aerobes 8.7 · 10⁶ <9.9 · 10¹ Fungi 3.0 · 10² <9.9 · 10¹Yeast 3.0 · 10² <9.9 · 10¹

[0047] At 28 days no increase has been detected from the 14 days' count.

Example 4

[0048] The composition of a formulation to obtain an aqueous solutionwith a surfactants' mixture, is (in g): Sodium lauryl sulfate (sol. 27%)14.00 Cocamidopropyl betaine 6.00 Disodium cocoamfoacetate 6.00 Lacticacid 0.25 Sodium chloride 0.50 Aqua 100 c.s.p.

[0049] This formulation is applied in bath gels.

[0050] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 5. TABLE 5 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 3.6 · 10⁶  3.3 · 10⁶Fungi 1.6 · 10⁴  1.9 · 10⁴ Yeast 3.9 · 10⁴  4.6 · 10⁴  7 days Aerobes4.2 · 10⁶  5.8 · 10³ Fungi 2.7 · 10³  2.7 · 10² Yeast 4.5 · 10³ <9.9 ·10¹ 14 days Aerobes 5.5 · 10⁶ <9.9 · 10¹ Fungi 3.4 · 10³ <9.9 · 10¹Yeast 5.9 · 10³ <9.9 · 10¹

[0051] At 28 days no increase has been detected from the 14 days' count.

Example 5

[0052] The composition of a formulation to obtain an aqueous solutionwith a surfactants' mixture, is (in g): Sodium lauryl sulfate (sol. 27%)14.00 Cocamidopropyl betaine 6.00 Disodium lauryl sulfosuccinate 6.00Lactic acid 0.25 Sodium chloride 0.50 Aqua 100 c.s.p.

[0053] This formulation is applied in bath gels.

[0054] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 6. TABLE 6 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 8.6 · 10⁶ 6.7 · 10⁶Fungi 1.1 · 10⁴ 1.4 · 10⁴ Yeast 3.2 · 10⁴ 3.6 · 10⁴  7 days Aerobes 3.9· 10⁷ 4.8 · 10² Fungi 1.6 · 10³ <9.9 · 10¹  Yeast 3.1 · 10³ <9.9 · 10¹ 14 days Aerobes 3.3 · 10⁶ 1.3 · 10² Fungi 8.3 · 10³ <9.9 · 10¹  Yeast3.9 · 10⁴ <9.9 · 10¹ 

[0055] At 28 days no increase has been detected from the 14 days' count.

Example 6

[0056] The composition of a formulation to obtain a hydroalcoholic gel,is (in g): Hydroxyethyl cellulose 0.40 Carbomer 940 0.40 Glycerin 8.00Alcohol denat 30.00 PEG 40 hydrogenated castor oil 1.50 Parfum 0.75Triethanolamine 0.25 Aqua 100 c.s.p.

[0057] This formulation is applied in lotions for after-shaving skincare.

[0058] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 7. TABLE 7 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 1.1 · 10⁶ 3.7 · 10⁶Fungi 8.7 · 10⁴ 9.1 · 10⁴ Yeast 3.9 · 10⁴ 4.2 · 10⁴  7 days Aerobes 4.6· 10⁶ 6.9 · 10³ Fungi 9.1 · 10³ 4.1 · 10² Yeast 8.6 · 10² 1.6 · 10² 14days Aerobes 7.3 · 10⁶ <9.9 · 10¹  Fungi 1.7 · 10³ <9.9 · 10¹  Yeast 1.2· 10³ <9.9 · 10¹ 

[0059] At 28 days no increase has been detected from the 14 days' count.

Example 7

[0060] The composition of a formulation to obtain a facial tonic, is (ing): Hydroxyethyl cellulose 0.20 Caprylic-caproic triglycerides 1.00 PEG40 hydrogenated castor oil 6.00 Lactic acid 1.00 Sodium chloride 0.35Glycerin 3.00 Chamomilla Recutita extract 3.00 Aqua 100 c.s.p.

[0061] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 8. TABLE 8 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 6.7 · 10⁶ 2.7 · 10⁶Fungi 4.1 · 10⁴ 2.1 · 10⁴ Yeast 3.2 · 10⁴ 1.2 · 10⁴  7 days Aerobes 3.7· 10⁷ 3.6 · 10³ Fungi 9.1 · 10³ 1.3 · 10² Yeast 4.2 · 10³ 1.1 · 10² 14days Aerobes 8.7 · 10⁷ 5.9 · 10² Fungi 2.1 · 10⁴ <9.9 · 10¹  Yeast 1.2 ·10⁴ <9.9 · 10¹ 

[0062] At 28 days no increase has been detected from the 14 days' count.

Example 8

[0063] The composition of a formulation to obtain a mask-up cleaner, is(in g): Stearic acid 2.00 Glyceryl stearate S.E 2.50 Cetyl alcohol 1.50Paraffinum 6.00 Isopropyl myristate 1.50 Caprylic-caproic triglycerides1.50 Dimethicone 0.50 Propylene glycol 3.00 Triethanolamine 1.20 Aqua100 c.s.p.

[0064] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 9. TABLE 9Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 5.5· 10⁶ 4.5 · 10⁶ Fungi 7.9 · 10⁴ 7.6 · 10⁴ Yeast 8.4 · 10⁴ 7.2 · 10⁴  7days Aerobes 6.5 · 10⁶ 3.8 · 10³ Fungi 8.2 · 10² 3.5 · 10² Yeast 8.8 ·10² 1.8 · 10² 14 days Aerobes 9.5 · 10⁶ 6.7 · 10² Fungi 2.9 · 10³ <9.9 ·10¹  Yeast 1.8 · 10³ <9.9 · 10¹ 

[0065] At 28 days no increase has been detected from the 14 days' count.

Example 9

[0066] The composition of a formulation to obtain a fluid oil-in-wateremulsion with non-ionic surfactants, is (in g): Polysorbate 60 3.00Sorbitan stearate 2.00 Cetyl alcohol 0.75 Paraffinum 3.00 Isopropylmyristate 2.50 Caprylic-caproic triglycerides 2.00 Dimethicone 0.50Propylene glycol 3.00 Aqua 100 c.s.p.

[0067] This formulation is applied in body oil.

[0068] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 10. TABLE 10Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 1.5· 10⁶ 4.5 · 10⁶ Fungi 2.6 · 10⁴ 7.6 · 10⁴ Yeast 3.2 · 10⁴ 7.2 · 10⁴  7days Aerobes 4.5 · 10⁶ 7.6 · 10³ Fungi 7.7 · 10³ 1.4 · 10² Yeast 8.4 ·10³ 2.3 · 10² 14 days Aerobes 6.3 · 10⁶ <9.9 · 10¹  Fungi 1.6 · 10⁴ <9.9· 10¹  Yeast 7.9 · 10³ <9.9 · 10¹ 

[0069] At 28 days no increase has been detected from the 14 days' count.

Example 10

[0070] The composition of a toothpaste formulation is (in g): Calciumcarbonate 16.00 Dicalcium phosphate 24.00 Silica 2.00 Petrolatum 10.00Glycerine 20.00 Sodium fluoride 0.20 Hydroxyethyl cellulose 1.00 Lauroylsarcosine 2.00 Aqua 100 c.s.p.

[0071] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 11. TABLE 11Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 6.5· 10⁶ 4.5 · 10⁶ Fungi 9.6 · 10⁴ 5.6 · 10⁴ Yeast 4.8 · 10⁴ 4.2 · 10⁴  7days Aerobes 3.5 · 10⁷ 3.3 · 10³ Fungi 1.6 · 10⁴ 1.6 · 10² Yeast 5.2 ·10³ 1.2 · 10² 14 days Aerobes 6.5 · 10⁷ 8.0 · 10² Fungi 1.7 · 10⁴ <9.9 ·10¹  Yeast 4.8 · 10³ <9.9 · 10¹ 

[0072] At 28 days no increase has been detected from the 14 days' count.

Example 11

[0073] The composition of a formulation to obtain an aqueous solutionwith surfactants, is (in g): Sodium lauryl sulfate (sol. 27%) 12.00Cocamidopropyl betaine 5.00 Disodium cocoamfoacetate 5.00Polyquaternium11 1.00 Lactic acid 0.25 Sodium chloride 0.50 Aqua 100c.s.p.

[0074] This formulation is applied in shampoos cosmetic formulations.

[0075] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 12. TABLE 12Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 3.7· 10⁶ 3.3 · 10⁶ Fungi 7.6 · 10⁴ 9.6 · 10⁴ Yeast 3.2 · 10⁴ 4.2 · 10⁴  7days Aerobes 5.9 · 10⁶ 4.8 · 10³ Fungi 9.6 · 10² 1.1 · 10² Yeast 4.9 ·10³ 1.2 · 10² 14 days Aerobes 6.3 · 10⁶ 7.0 · 10² Fungi 1.1 · 10³ <9.9 ·10¹  Yeast 5.2 · 10³ <9.9 · 10¹ 

[0076] At 28 days no increase has been detected from the 14 days' count.

Example 12

[0077] The composition of a formulation to obtain an oil-in-wateremulsion with non-ionic surfactants, is (in g): Glyceryl stearate + PEG100 stearate 4.00 Cetyl alcohol + sodium cetyl sulfate 2.00Caprylic-caproic triglycerides 4.00 Isopropyl mirystate 2.50 Paraffinum2.00 Dimethicone 0.50 Glycerin 3.00 Wheat (triticum vulgare) germprotein 2.00 Aqua 100 c.s.p.

[0078] This formulation is applied in a face cream for skin care.

[0079] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 13. TABLE 13 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 3.3 · 10⁶ 1.1 · 10⁶Fungi 1.6 · 10⁴ 1.7 · 10⁴ Yeast 2.2 · 10⁴ 3.2 · 10⁴  7 days Aerobes 4.3· 10⁶ 3.7 · 10⁴ Fungi 1.9 · 10² 8.7 · 10² Yeast 2.5 · 10² 9.2 · 10² 14days Aerobes 4.3 · 10⁶ 1.9 · 10³ Fungi 1.8 · 10² <9.9 · 10¹  Yeast 2.9 ·10² <9.9 · 10¹ 

[0080] At 28 days no increase has been detected from the 14 days' count.

Example 13

[0081] The composition of a formulation to obtain an oil-in-wateremulsion with non-ionic surfactants, is (in g): Polysorbate 60 3.00Sorbitan stearate 2.00 Cetyl alcohol 2.50 Paraffinum 2.00Caprylic-caproic triglycerides 2.00 Ethyl hexyl methoxycinnamate 5.00Benzophenone 3 1.00 Dimethicone 0.50 Propylene glycol 3.00 Aqua 100c.s.p.

[0082] This formulation is applied in a sun protector cosmeticformulator.

[0083] This formulation is completed with 0.20 g of LAE and its capacityof preservation is evaluated against the formulation without LAE. Theresults are shown in the Table 14. TABLE 14 Without LAE With LAEMicroorganism (cfu/mL) (cfu/mL) Initial Aerobes 4.4 · 10⁶ 3.1 · 10⁶Fungi 5.7 · 10⁴ 4.9 · 10⁴ Yeast 2.7 · 10⁴ 3.8 · 10⁴  7 days Aerobes 6.3· 10⁶ 8.4 · 10³ Fungi 5.1 · 10² 2.7 · 10² Yeast 2.3 · 10² 4.2 · 10² 14days Aerobes 7.2 · 10⁶ 7.5 · 10² Fungi 5.9 · 10² <9.9 · 10¹  Yeast 2.8 ·10² <9.9 · 10¹ 

[0084] At 28 days no increase has been detected from the 14 days' count.

Example 14

[0085] The composition of a formulation to obtain an oil-in-wateremulsion with non-ionic surfactants is (in g): Cetyl Dimethiconecopolyol 3.00 Isohexadecane 4.00 Paraffinum 5.00 Isopropyl myristate3.00 Caprylic-caproic triglycerides 3.00 Ethyl hexyl methoxycinnamate5.00 Benzophenone 3 1.00 Glycerin 3.00 Sodium chloride 0.50 Aqua 100c.s.p.

[0086] This formulation is applied in a sun protector cosmetic product.

[0087] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 15. TABLE 15Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 2.8· 10⁶ 1.4 · 10⁶ Fungi 5.5 · 10⁴ 5.3 · 10⁴ Yeast 7.7 · 10⁴ 7.9 · 10⁴  7days Aerobes 4.4 · 10⁶ 9.4 · 10² Fungi 8.6 · 10² 6.7 · 10² Yeast 8.3 ·10² 4.5 · 10² 14 days Aerobes 7.2 · 10⁶ 8.7 · 10² Fungi 5.8 · 10² <9.9 ·10¹  Yeast 7.9 · 10² <9.9 · 10¹ 

[0088] At 28 days no increase has been detected from the 14 days' count.

Example 15

[0089] The composition of a formulation to obtain an emulsion for handscare, is (in g): Cetyl alcohol + ceteareth 20 6.00 Isopropyl myristate2.00 Caprylic-caproic triglycerides 1.00 Dimethicone 1.00 Benzophenone 31.00 Glycerin 6.00 Carbomer 940 0.10 Triethanolamine 0.10 Aqua 100c.s.p.

[0090] This formulation is completed with 0.20 g of LAE, and thepreservative capacity is evaluated and it is compared with theformulation without LAE. The results are shown in the Table 16. TABLE 16Without LAE With LAE Microorganism (cfu/mL) (cfu/mL) Initial Aerobes 4.5· 10⁶ 4.4 · 10⁶ Fungi 6.1 · 10⁴ 5.8 · 10⁴ Yeast 8.8 · 10⁴ 8.6 · 10⁴  7days Aerobes 7.4 · 10⁶ 3.3 · 10³ Fungi 7.8 · 10² 8.7 · 10² Yeast 8.9 ·10² 7.2 · 10² 14 days Aerobes 4.4 · 10⁶ <9.9 · 10¹  Fungi 9.8 · 10² <9.9· 10¹  Yeast 1.2 · 10³ <9.9 · 10¹ 

[0091] At 28 days no increase has been detected from the 14 days' count.

1. Use of cationic surfactants derived from the condensation of fattyacids and esterified dibasic amino acids, according to the followingformula:

where: X⁻ is Br⁻, Cl⁻, or HSO₄ ⁻ R₁: is linear alkyl chain from ansaturated fatty acid, or hydroxyacid from 8 to 14 atoms of carbon bondedto the α-amino acid group through amidic bond. R₂: is a lineal orbranched alkyl chain from 1 to 18 carbon atoms or aromatic. R₃: is:

and n can be from 0 to 4, as preservatives in cosmetic or dermatologicalpreparations.
 2. The use according to claim 1, wherein the cationicsurfactant is the ethyl ester of the lauramide of arginine hydrochloride(LAE).
 3. A cosmetic or dermatological composition comprising thecationic surfactant defined in claim 1 or 2 as a preservative.
 4. Thecosmetic or dermatological composition of claim 3, wherein the cationicsurfactant is LAE at a concentration of from 0.001 to 2%.
 5. Compositionaccording to the claim 3 or 4 further comprising fatty compounds such asmineral oil, animals, vegetal, from synthesis and silicon, and alsoalcohol, fatty acids and waxes; organic solvents, surface active agents,solubilizers and ionic and non ionic emulsifiers, thickening agents andjellying hydrophilic agents such as carboxyvinylic polymers (e.g.carbomer), acrylic copolymers (e.g. acrylates and alkylacrylates),polyacrylamides, polysaccharides, natural gums (e.g. xanthan gum);thickening agents and jellying lipophilic agents such as modified clays(e.g. bentonite), fatty acid metallic salts, hydrophobic silica andpolyethylene; perfumes and essential oils; softening agents; excipients;antioxidants; sequestering agents; opacifiers; filters; colouringcompounds hydrosolubles and liposolubles, and pigments; and hydrophilicor lipophilic active ingredients.
 6. Composition according to the claims3 to 5 in the form of an aqueous, hydroalcoholic, or hydroglycolicsolution, of an emulsion, microemulsion, aqueous or anhydrous gel or ofa vesicle dispersion.
 7. Composition according to any of claims 3 to 6for skin care.